Problem: Convert $7\ \dfrac{13}{21}$ to an improper fraction.
Solution: ${7}\ {\dfrac{13}{21}}$ This mixed number is equivalent to ${7} + {\dfrac{13}{21}}$ First, convert the whole part of the mixed number to a fraction with the same denominator $21$ as the fractional part ${7} \times \dfrac{21}{21} = {\dfrac{147}{21}}$ So now we have our number in the form ${\dfrac{147}{21}} + {\dfrac{13}{21}}$ Now, just add the two fractions and simplify! ${\dfrac{147}{21}} + {\dfrac{13}{21}} = \dfrac{160}{21}$